High risk for cardiovascular disease in Chinese type 2 diabetic patients with major depression--a 7-year prospective analysis of the Hong Kong Diabetes Registry

Abstract

Background: Depression is known to be associated with premature mortality and cardiovascular disease (CVD) in type 2 diabetes, although there is a paucity of similar data in Chinese population. In this study, we examined the risk association of major depression with premature mortality and CVD in a hospital clinic-based cohort.

Methods: In a prospective cohort of 7835 Hong Kong Chinese with type 2 diabetes but without CVD at baseline, 153 patients were diagnosed with major depression by psychiatrists in public hospitals. After a median follow-up period of 7.4 years, 827 patients died and 829 patients developed CVD mainly due to stroke (n=384). We used Cox proportional hazard regression to obtain the hazard ratio (HR, 95% confidence interval, CI) of depression for the risk of mortality and CVD.

Results: Depressed patients were younger (51.6 versus 56.6 years, p<0.001), more likely to be female (78.4% versus 53.0%, p<0.001), had higher LDL-cholesterol (3.2 versus 3.0 mmol/L, p=0.038) at baseline and longer hospitalization stays per year (median:0.8 nights per 100-person-years versus 0.1 nights per 100-person-years, p<0.001). After adjusting for conventional risk factors, depression independently predicted CVD [HR=2.18(95% CI=1.45-3.27)], mainly due to stroke [HR=3.55(95% CI=2.15-5.84)].

Limitations: The young age and small sample size of patients with depression did not give sufficient power to confirm risk association of depression with premature mortality and myocardial infarction.

Conclusions: In Chinese type 2 diabetic patients, depression was associated with a 2-3 fold increase in the risk of incident CVD, especially stroke.